AutoScaling / Client / start_instance_refresh

start_instance_refresh

AutoScaling.Client.start_instance_refresh(**kwargs)

Starts an instance refresh.

This operation is part of the instance refresh feature in Amazon EC2 Auto Scaling, which helps you update instances in your Auto Scaling group. This feature is helpful, for example, when you have a new AMI or a new user data script. You just need to create a new launch template that specifies the new AMI or user data script. Then start an instance refresh to immediately begin the process of updating instances in the group.

If successful, the request’s response contains a unique ID that you can use to track the progress of the instance refresh. To query its status, call the DescribeInstanceRefreshes API. To describe the instance refreshes that have already run, call the DescribeInstanceRefreshes API. To cancel an instance refresh that is in progress, use the CancelInstanceRefresh API.

An instance refresh might fail for several reasons, such as EC2 launch failures, misconfigured health checks, or not ignoring or allowing the termination of instances that are in Standby state or protected from scale in. You can monitor for failed EC2 launches using the scaling activities. To find the scaling activities, call the DescribeScalingActivities API.

If you enable auto rollback, your Auto Scaling group will be rolled back automatically when the instance refresh fails. You can enable this feature before starting an instance refresh by specifying the AutoRollback property in the instance refresh preferences. Otherwise, to roll back an instance refresh before it finishes, use the RollbackInstanceRefresh API.

See also: AWS API Documentation

Request Syntax

response = client.start_instance_refresh(
    AutoScalingGroupName='string',
    Strategy='Rolling',
    DesiredConfiguration={
        'LaunchTemplate': {
            'LaunchTemplateId': 'string',
            'LaunchTemplateName': 'string',
            'Version': 'string'
        },
        'MixedInstancesPolicy': {
            'LaunchTemplate': {
                'LaunchTemplateSpecification': {
                    'LaunchTemplateId': 'string',
                    'LaunchTemplateName': 'string',
                    'Version': 'string'
                },
                'Overrides': [
                    {
                        'InstanceType': 'string',
                        'WeightedCapacity': 'string',
                        'LaunchTemplateSpecification': {
                            'LaunchTemplateId': 'string',
                            'LaunchTemplateName': 'string',
                            'Version': 'string'
                        },
                        'InstanceRequirements': {
                            'VCpuCount': {
                                'Min': 123,
                                'Max': 123
                            },
                            'MemoryMiB': {
                                'Min': 123,
                                'Max': 123
                            },
                            'CpuManufacturers': [
                                'intel'|'amd'|'amazon-web-services',
                            ],
                            'MemoryGiBPerVCpu': {
                                'Min': 123.0,
                                'Max': 123.0
                            },
                            'ExcludedInstanceTypes': [
                                'string',
                            ],
                            'InstanceGenerations': [
                                'current'|'previous',
                            ],
                            'SpotMaxPricePercentageOverLowestPrice': 123,
                            'MaxSpotPriceAsPercentageOfOptimalOnDemandPrice': 123,
                            'OnDemandMaxPricePercentageOverLowestPrice': 123,
                            'BareMetal': 'included'|'excluded'|'required',
                            'BurstablePerformance': 'included'|'excluded'|'required',
                            'RequireHibernateSupport': True|False,
                            'NetworkInterfaceCount': {
                                'Min': 123,
                                'Max': 123
                            },
                            'LocalStorage': 'included'|'excluded'|'required',
                            'LocalStorageTypes': [
                                'hdd'|'ssd',
                            ],
                            'TotalLocalStorageGB': {
                                'Min': 123.0,
                                'Max': 123.0
                            },
                            'BaselineEbsBandwidthMbps': {
                                'Min': 123,
                                'Max': 123
                            },
                            'AcceleratorTypes': [
                                'gpu'|'fpga'|'inference',
                            ],
                            'AcceleratorCount': {
                                'Min': 123,
                                'Max': 123
                            },
                            'AcceleratorManufacturers': [
                                'nvidia'|'amd'|'amazon-web-services'|'xilinx',
                            ],
                            'AcceleratorNames': [
                                'a100'|'v100'|'k80'|'t4'|'m60'|'radeon-pro-v520'|'vu9p',
                            ],
                            'AcceleratorTotalMemoryMiB': {
                                'Min': 123,
                                'Max': 123
                            },
                            'NetworkBandwidthGbps': {
                                'Min': 123.0,
                                'Max': 123.0
                            },
                            'AllowedInstanceTypes': [
                                'string',
                            ]
                        }
                    },
                ]
            },
            'InstancesDistribution': {
                'OnDemandAllocationStrategy': 'string',
                'OnDemandBaseCapacity': 123,
                'OnDemandPercentageAboveBaseCapacity': 123,
                'SpotAllocationStrategy': 'string',
                'SpotInstancePools': 123,
                'SpotMaxPrice': 'string'
            }
        }
    },
    Preferences={
        'MinHealthyPercentage': 123,
        'InstanceWarmup': 123,
        'CheckpointPercentages': [
            123,
        ],
        'CheckpointDelay': 123,
        'SkipMatching': True|False,
        'AutoRollback': True|False,
        'ScaleInProtectedInstances': 'Refresh'|'Ignore'|'Wait',
        'StandbyInstances': 'Terminate'|'Ignore'|'Wait',
        'AlarmSpecification': {
            'Alarms': [
                'string',
            ]
        },
        'MaxHealthyPercentage': 123
    }
)

Parameters:

• AutoScalingGroupName (string) –

  [REQUIRED]

  The name of the Auto Scaling group.

• Strategy (string) – The strategy to use for the instance refresh. The only valid value is Rolling.

• DesiredConfiguration (dict) –

  The desired configuration. For example, the desired configuration can specify a new launch template or a new version of the current launch template.

  Once the instance refresh succeeds, Amazon EC2 Auto Scaling updates the settings of the Auto Scaling group to reflect the new desired configuration.

  Note

  When you specify a new launch template or a new version of the current launch template for your desired configuration, consider enabling the SkipMatching property in preferences. If it’s enabled, Amazon EC2 Auto Scaling skips replacing instances that already use the specified launch template and instance types. This can help you reduce the number of replacements that are required to apply updates.

  • LaunchTemplate (dict) –

    Describes the launch template and the version of the launch template that Amazon EC2 Auto Scaling uses to launch Amazon EC2 instances. For more information about launch templates, see Launch templates in the Amazon EC2 Auto Scaling User Guide.

    • LaunchTemplateId (string) –

      The ID of the launch template. To get the template ID, use the Amazon EC2 DescribeLaunchTemplates API operation. New launch templates can be created using the Amazon EC2 CreateLaunchTemplate API.

      Conditional: You must specify either a LaunchTemplateId or a LaunchTemplateName.

    • LaunchTemplateName (string) –

      The name of the launch template. To get the template name, use the Amazon EC2 DescribeLaunchTemplates API operation. New launch templates can be created using the Amazon EC2 CreateLaunchTemplate API.

      Conditional: You must specify either a LaunchTemplateId or a LaunchTemplateName.

    • Version (string) –

      The version number, $Latest, or $Default. To get the version number, use the Amazon EC2 DescribeLaunchTemplateVersions API operation. New launch template versions can be created using the Amazon EC2 CreateLaunchTemplateVersion API. If the value is $Latest, Amazon EC2 Auto Scaling selects the latest version of the launch template when launching instances. If the value is $Default, Amazon EC2 Auto Scaling selects the default version of the launch template when launching instances. The default value is $Default.

  • MixedInstancesPolicy (dict) –

    Use this structure to launch multiple instance types and On-Demand Instances and Spot Instances within a single Auto Scaling group.

    A mixed instances policy contains information that Amazon EC2 Auto Scaling can use to launch instances and help optimize your costs. For more information, see Auto Scaling groups with multiple instance types and purchase options in the Amazon EC2 Auto Scaling User Guide.

    • LaunchTemplate (dict) –

      One or more launch templates and the instance types (overrides) that are used to launch EC2 instances to fulfill On-Demand and Spot capacities.

      • LaunchTemplateSpecification (dict) –

        The launch template.

        • LaunchTemplateId (string) –

          The ID of the launch template. To get the template ID, use the Amazon EC2 DescribeLaunchTemplates API operation. New launch templates can be created using the Amazon EC2 CreateLaunchTemplate API.

          Conditional: You must specify either a LaunchTemplateId or a LaunchTemplateName.

        • LaunchTemplateName (string) –

          The name of the launch template. To get the template name, use the Amazon EC2 DescribeLaunchTemplates API operation. New launch templates can be created using the Amazon EC2 CreateLaunchTemplate API.

          Conditional: You must specify either a LaunchTemplateId or a LaunchTemplateName.

        • Version (string) –

          The version number, $Latest, or $Default. To get the version number, use the Amazon EC2 DescribeLaunchTemplateVersions API operation. New launch template versions can be created using the Amazon EC2 CreateLaunchTemplateVersion API. If the value is $Latest, Amazon EC2 Auto Scaling selects the latest version of the launch template when launching instances. If the value is $Default, Amazon EC2 Auto Scaling selects the default version of the launch template when launching instances. The default value is $Default.

      • Overrides (list) –

        Any properties that you specify override the same properties in the launch template.

        • (dict) –

          Use this structure to let Amazon EC2 Auto Scaling do the following when the Auto Scaling group has a mixed instances policy:

          • Override the instance type that is specified in the launch template.

          • Use multiple instance types.

          Specify the instance types that you want, or define your instance requirements instead and let Amazon EC2 Auto Scaling provision the available instance types that meet your requirements. This can provide Amazon EC2 Auto Scaling with a larger selection of instance types to choose from when fulfilling Spot and On-Demand capacities. You can view which instance types are matched before you apply the instance requirements to your Auto Scaling group.

          After you define your instance requirements, you don’t have to keep updating these settings to get new EC2 instance types automatically. Amazon EC2 Auto Scaling uses the instance requirements of the Auto Scaling group to determine whether a new EC2 instance type can be used.

          • InstanceType (string) –

            The instance type, such as m3.xlarge. You must specify an instance type that is supported in your requested Region and Availability Zones. For more information, see Instance types in the Amazon Elastic Compute Cloud User Guide.

            You can specify up to 40 instance types per Auto Scaling group.

          • WeightedCapacity (string) –

            If you provide a list of instance types to use, you can specify the number of capacity units provided by each instance type in terms of virtual CPUs, memory, storage, throughput, or other relative performance characteristic. When a Spot or On-Demand Instance is launched, the capacity units count toward the desired capacity. Amazon EC2 Auto Scaling launches instances until the desired capacity is totally fulfilled, even if this results in an overage. For example, if there are two units remaining to fulfill capacity, and Amazon EC2 Auto Scaling can only launch an instance with a WeightedCapacity of five units, the instance is launched, and the desired capacity is exceeded by three units. For more information, see Configuring instance weighting for Amazon EC2 Auto Scaling in the Amazon EC2 Auto Scaling User Guide. Value must be in the range of 1–999.

            If you specify a value for WeightedCapacity for one instance type, you must specify a value for WeightedCapacity for all of them.

            Warning

            Every Auto Scaling group has three size parameters ( DesiredCapacity, MaxSize, and MinSize). Usually, you set these sizes based on a specific number of instances. However, if you configure a mixed instances policy that defines weights for the instance types, you must specify these sizes with the same units that you use for weighting instances.

          • LaunchTemplateSpecification (dict) –

            Provides a launch template for the specified instance type or set of instance requirements. For example, some instance types might require a launch template with a different AMI. If not provided, Amazon EC2 Auto Scaling uses the launch template that’s specified in the LaunchTemplate definition. For more information, see Specifying a different launch template for an instance type in the Amazon EC2 Auto Scaling User Guide.

            You can specify up to 20 launch templates per Auto Scaling group. The launch templates specified in the overrides and in the LaunchTemplate definition count towards this limit.

            • LaunchTemplateId (string) –

              The ID of the launch template. To get the template ID, use the Amazon EC2 DescribeLaunchTemplates API operation. New launch templates can be created using the Amazon EC2 CreateLaunchTemplate API.

              Conditional: You must specify either a LaunchTemplateId or a LaunchTemplateName.

            • LaunchTemplateName (string) –

              The name of the launch template. To get the template name, use the Amazon EC2 DescribeLaunchTemplates API operation. New launch templates can be created using the Amazon EC2 CreateLaunchTemplate API.

              Conditional: You must specify either a LaunchTemplateId or a LaunchTemplateName.

            • Version (string) –

              The version number, $Latest, or $Default. To get the version number, use the Amazon EC2 DescribeLaunchTemplateVersions API operation. New launch template versions can be created using the Amazon EC2 CreateLaunchTemplateVersion API. If the value is $Latest, Amazon EC2 Auto Scaling selects the latest version of the launch template when launching instances. If the value is $Default, Amazon EC2 Auto Scaling selects the default version of the launch template when launching instances. The default value is $Default.

          • InstanceRequirements (dict) –

            The instance requirements. Amazon EC2 Auto Scaling uses your specified requirements to identify instance types. Then, it uses your On-Demand and Spot allocation strategies to launch instances from these instance types.

            You can specify up to four separate sets of instance requirements per Auto Scaling group. This is useful for provisioning instances from different Amazon Machine Images (AMIs) in the same Auto Scaling group. To do this, create the AMIs and create a new launch template for each AMI. Then, create a compatible set of instance requirements for each launch template.

            Note

            If you specify InstanceRequirements, you can’t specify InstanceType.

            • VCpuCount (dict) – [REQUIRED]

              The minimum and maximum number of vCPUs for an instance type.

              • Min (integer) – [REQUIRED]

                The minimum number of vCPUs.

              • Max (integer) –

                The maximum number of vCPUs.

            • MemoryMiB (dict) – [REQUIRED]

              The minimum and maximum instance memory size for an instance type, in MiB.

              • Min (integer) – [REQUIRED]

                The memory minimum in MiB.

              • Max (integer) –

                The memory maximum in MiB.

            • CpuManufacturers (list) –

              Lists which specific CPU manufacturers to include.

              • For instance types with Intel CPUs, specify intel.

              • For instance types with AMD CPUs, specify amd.

              • For instance types with Amazon Web Services CPUs, specify amazon-web-services.

              Note

              Don’t confuse the CPU hardware manufacturer with the CPU hardware architecture. Instances will be launched with a compatible CPU architecture based on the Amazon Machine Image (AMI) that you specify in your launch template.

              Default: Any manufacturer

              • (string) –

            • MemoryGiBPerVCpu (dict) –

              The minimum and maximum amount of memory per vCPU for an instance type, in GiB.

              Default: No minimum or maximum limits

              • Min (float) –

                The memory minimum in GiB.

              • Max (float) –

                The memory maximum in GiB.

            • ExcludedInstanceTypes (list) –

              The instance types to exclude. You can use strings with one or more wild cards, represented by an asterisk ( *), to exclude an instance family, type, size, or generation. The following are examples: m5.8xlarge, c5*.*, m5a.*, r*, *3*.

              For example, if you specify c5*, you are excluding the entire C5 instance family, which includes all C5a and C5n instance types. If you specify m5a.*, Amazon EC2 Auto Scaling will exclude all the M5a instance types, but not the M5n instance types.

              Note

              If you specify ExcludedInstanceTypes, you can’t specify AllowedInstanceTypes.

              Default: No excluded instance types

              • (string) –

            • InstanceGenerations (list) –

              Indicates whether current or previous generation instance types are included.

              • For current generation instance types, specify current. The current generation includes EC2 instance types currently recommended for use. This typically includes the latest two to three generations in each instance family. For more information, see Instance types in the Amazon EC2 User Guide for Linux Instances.

              • For previous generation instance types, specify previous.

              Default: Any current or previous generation

              • (string) –

            • SpotMaxPricePercentageOverLowestPrice (integer) –

              [Price protection] The price protection threshold for Spot Instances, as a percentage higher than an identified Spot price. The identified Spot price is the price of the lowest priced current generation C, M, or R instance type with your specified attributes. If no current generation C, M, or R instance type matches your attributes, then the identified price is from either the lowest priced current generation instance types or, failing that, the lowest priced previous generation instance types that match your attributes. When Amazon EC2 Auto Scaling selects instance types with your attributes, we will exclude instance types whose price exceeds your specified threshold.

              The parameter accepts an integer, which Amazon EC2 Auto Scaling interprets as a percentage.

              To turn off price protection, specify a high value, such as 999999.

              If you set DesiredCapacityType to vcpu or memory-mib, the price protection threshold is based on the per-vCPU or per-memory price instead of the per instance price.

              Note

              Only one of SpotMaxPricePercentageOverLowestPrice or MaxSpotPriceAsPercentageOfOptimalOnDemandPrice can be specified.

              Default: 100

            • MaxSpotPriceAsPercentageOfOptimalOnDemandPrice (integer) –

              [Price protection] The price protection threshold for Spot Instances, as a percentage of an identified On-Demand price. The identified On-Demand price is the price of the lowest priced current generation C, M, or R instance type with your specified attributes. If no current generation C, M, or R instance type matches your attributes, then the identified price is from either the lowest priced current generation instance types or, failing that, the lowest priced previous generation instance types that match your attributes. When Amazon EC2 Auto Scaling selects instance types with your attributes, we will exclude instance types whose price exceeds your specified threshold.

              The parameter accepts an integer, which Amazon EC2 Auto Scaling interprets as a percentage.

              To indicate no price protection threshold, specify a high value, such as 999999.

              If you set DesiredCapacityType to vcpu or memory-mib, the price protection threshold is based on the per-vCPU or per-memory price instead of the per instance price.

              Note

              Only one of SpotMaxPricePercentageOverLowestPrice or MaxSpotPriceAsPercentageOfOptimalOnDemandPrice can be specified. If you don’t specify either, then SpotMaxPricePercentageOverLowestPrice is used and the value for that parameter defaults to 100.

            • OnDemandMaxPricePercentageOverLowestPrice (integer) –

              [Price protection] The price protection threshold for On-Demand Instances, as a percentage higher than an identified On-Demand price. The identified On-Demand price is the price of the lowest priced current generation C, M, or R instance type with your specified attributes. If no current generation C, M, or R instance type matches your attributes, then the identified price is from either the lowest priced current generation instance types or, failing that, the lowest priced previous generation instance types that match your attributes. When Amazon EC2 Auto Scaling selects instance types with your attributes, we will exclude instance types whose price exceeds your specified threshold.

              The parameter accepts an integer, which Amazon EC2 Auto Scaling interprets as a percentage.

              To turn off price protection, specify a high value, such as 999999.

              If you set DesiredCapacityType to vcpu or memory-mib, the price protection threshold is applied based on the per-vCPU or per-memory price instead of the per instance price.

              Default: 20

            • BareMetal (string) –

              Indicates whether bare metal instance types are included, excluded, or required.

              Default: excluded

            • BurstablePerformance (string) –

              Indicates whether burstable performance instance types are included, excluded, or required. For more information, see Burstable performance instances in the Amazon EC2 User Guide for Linux Instances.

              Default: excluded

            • RequireHibernateSupport (boolean) –

              Indicates whether instance types must provide On-Demand Instance hibernation support.

              Default: false

            • NetworkInterfaceCount (dict) –

              The minimum and maximum number of network interfaces for an instance type.

              Default: No minimum or maximum limits

              • Min (integer) –

                The minimum number of network interfaces.

              • Max (integer) –

                The maximum number of network interfaces.

            • LocalStorage (string) –

              Indicates whether instance types with instance store volumes are included, excluded, or required. For more information, see Amazon EC2 instance store in the Amazon EC2 User Guide for Linux Instances.

              Default: included

            • LocalStorageTypes (list) –

              Indicates the type of local storage that is required.

              • For instance types with hard disk drive (HDD) storage, specify hdd.

              • For instance types with solid state drive (SSD) storage, specify ssd.

              Default: Any local storage type

              • (string) –

            • TotalLocalStorageGB (dict) –

              The minimum and maximum total local storage size for an instance type, in GB.

              Default: No minimum or maximum limits

              • Min (float) –

                The storage minimum in GB.

              • Max (float) –

                The storage maximum in GB.

            • BaselineEbsBandwidthMbps (dict) –

              The minimum and maximum baseline bandwidth performance for an instance type, in Mbps. For more information, see Amazon EBS–optimized instances in the Amazon EC2 User Guide for Linux Instances.

              Default: No minimum or maximum limits

              • Min (integer) –

                The minimum value in Mbps.

              • Max (integer) –

                The maximum value in Mbps.

            • AcceleratorTypes (list) –

              Lists the accelerator types that must be on an instance type.

              • For instance types with GPU accelerators, specify gpu.

              • For instance types with FPGA accelerators, specify fpga.

              • For instance types with inference accelerators, specify inference.

              Default: Any accelerator type

              • (string) –

            • AcceleratorCount (dict) –

              The minimum and maximum number of accelerators (GPUs, FPGAs, or Amazon Web Services Inferentia chips) for an instance type.

              To exclude accelerator-enabled instance types, set Max to 0.

              Default: No minimum or maximum limits

              • Min (integer) –

                The minimum value.

              • Max (integer) –

                The maximum value.

            • AcceleratorManufacturers (list) –

              Indicates whether instance types must have accelerators by specific manufacturers.

              • For instance types with NVIDIA devices, specify nvidia.

              • For instance types with AMD devices, specify amd.

              • For instance types with Amazon Web Services devices, specify amazon-web-services.

              • For instance types with Xilinx devices, specify xilinx.

              Default: Any manufacturer

              • (string) –

            • AcceleratorNames (list) –

              Lists the accelerators that must be on an instance type.

              • For instance types with NVIDIA A100 GPUs, specify a100.

              • For instance types with NVIDIA V100 GPUs, specify v100.

              • For instance types with NVIDIA K80 GPUs, specify k80.

              • For instance types with NVIDIA T4 GPUs, specify t4.

              • For instance types with NVIDIA M60 GPUs, specify m60.

              • For instance types with AMD Radeon Pro V520 GPUs, specify radeon-pro-v520.

              • For instance types with Xilinx VU9P FPGAs, specify vu9p.

              Default: Any accelerator

              • (string) –

            • AcceleratorTotalMemoryMiB (dict) –

              The minimum and maximum total memory size for the accelerators on an instance type, in MiB.

              Default: No minimum or maximum limits

              • Min (integer) –

                The memory minimum in MiB.

              • Max (integer) –

                The memory maximum in MiB.

            • NetworkBandwidthGbps (dict) –

              The minimum and maximum amount of network bandwidth, in gigabits per second (Gbps).

              Default: No minimum or maximum limits

              • Min (float) –

                The minimum amount of network bandwidth, in gigabits per second (Gbps).

              • Max (float) –

                The maximum amount of network bandwidth, in gigabits per second (Gbps).

            • AllowedInstanceTypes (list) –

              The instance types to apply your specified attributes against. All other instance types are ignored, even if they match your specified attributes.

              You can use strings with one or more wild cards, represented by an asterisk ( *), to allow an instance type, size, or generation. The following are examples: m5.8xlarge, c5*.*, m5a.*, r*, *3*.

              For example, if you specify c5*, Amazon EC2 Auto Scaling will allow the entire C5 instance family, which includes all C5a and C5n instance types. If you specify m5a.*, Amazon EC2 Auto Scaling will allow all the M5a instance types, but not the M5n instance types.

              Note

              If you specify AllowedInstanceTypes, you can’t specify ExcludedInstanceTypes.

              Default: All instance types

              • (string) –

    • InstancesDistribution (dict) –

      The instances distribution.

      • OnDemandAllocationStrategy (string) –

        The allocation strategy to apply to your On-Demand Instances when they are launched. Possible instance types are determined by the launch template overrides that you specify.

        The following lists the valid values:

        lowest-price

        Uses price to determine which instance types are the highest priority, launching the lowest priced instance types within an Availability Zone first. This is the default value for Auto Scaling groups that specify InstanceRequirements.

        prioritized

        You set the order of instance types for the launch template overrides from highest to lowest priority (from first to last in the list). Amazon EC2 Auto Scaling launches your highest priority instance types first. If all your On-Demand capacity cannot be fulfilled using your highest priority instance type, then Amazon EC2 Auto Scaling launches the remaining capacity using the second priority instance type, and so on. This is the default value for Auto Scaling groups that don’t specify InstanceRequirements and cannot be used for groups that do.

      • OnDemandBaseCapacity (integer) –

        The minimum amount of the Auto Scaling group’s capacity that must be fulfilled by On-Demand Instances. This base portion is launched first as your group scales.

        This number has the same unit of measurement as the group’s desired capacity. If you change the default unit of measurement (number of instances) by specifying weighted capacity values in your launch template overrides list, or by changing the default desired capacity type setting of the group, you must specify this number using the same unit of measurement.

        Default: 0

      • OnDemandPercentageAboveBaseCapacity (integer) –

        Controls the percentages of On-Demand Instances and Spot Instances for your additional capacity beyond OnDemandBaseCapacity. Expressed as a number (for example, 20 specifies 20% On-Demand Instances, 80% Spot Instances). If set to 100, only On-Demand Instances are used.

        Default: 100

      • SpotAllocationStrategy (string) –

        The allocation strategy to apply to your Spot Instances when they are launched. Possible instance types are determined by the launch template overrides that you specify.

        The following lists the valid values:

        capacity-optimized

        Requests Spot Instances using pools that are optimally chosen based on the available Spot capacity. This strategy has the lowest risk of interruption. To give certain instance types a higher chance of launching first, use capacity-optimized-prioritized.

        capacity-optimized-prioritized

        You set the order of instance types for the launch template overrides from highest to lowest priority (from first to last in the list). Amazon EC2 Auto Scaling honors the instance type priorities on a best effort basis but optimizes for capacity first. Note that if the On-Demand allocation strategy is set to prioritized, the same priority is applied when fulfilling On-Demand capacity. This is not a valid value for Auto Scaling groups that specify InstanceRequirements.

        lowest-price

        Requests Spot Instances using the lowest priced pools within an Availability Zone, across the number of Spot pools that you specify for the SpotInstancePools property. To ensure that your desired capacity is met, you might receive Spot Instances from several pools. This is the default value, but it might lead to high interruption rates because this strategy only considers instance price and not available capacity.

        price-capacity-optimized (recommended)

        The price and capacity optimized allocation strategy looks at both price and capacity to select the Spot Instance pools that are the least likely to be interrupted and have the lowest possible price.

      • SpotInstancePools (integer) –

        The number of Spot Instance pools across which to allocate your Spot Instances. The Spot pools are determined from the different instance types in the overrides. Valid only when the SpotAllocationStrategy is lowest-price. Value must be in the range of 1–20.

        Default: 2

      • SpotMaxPrice (string) –

        The maximum price per unit hour that you are willing to pay for a Spot Instance. If your maximum price is lower than the Spot price for the instance types that you selected, your Spot Instances are not launched. We do not recommend specifying a maximum price because it can lead to increased interruptions. When Spot Instances launch, you pay the current Spot price. To remove a maximum price that you previously set, include the property but specify an empty string (“”) for the value.

        Warning

        If you specify a maximum price, your instances will be interrupted more frequently than if you do not specify one.

        Valid Range: Minimum value of 0.001

• Preferences (dict) –

  Sets your preferences for the instance refresh so that it performs as expected when you start it. Includes the instance warmup time, the minimum and maximum healthy percentages, and the behaviors that you want Amazon EC2 Auto Scaling to use if instances that are in Standby state or protected from scale in are found. You can also choose to enable additional features, such as the following:

  • Auto rollback

  • Checkpoints

  • CloudWatch alarms

  • Skip matching

  • MinHealthyPercentage (integer) –

    Specifies the minimum percentage of the group to keep in service, healthy, and ready to use to support your workload to allow the operation to continue. The value is expressed as a percentage of the desired capacity of the Auto Scaling group. Value range is 0 to 100.

    If you do not specify this property, the default is 90 percent, or the percentage set in the instance maintenance policy for the Auto Scaling group, if defined.

  • InstanceWarmup (integer) –

    A time period, in seconds, during which an instance refresh waits before moving on to replacing the next instance after a new instance enters the InService state.

    This property is not required for normal usage. Instead, use the DefaultInstanceWarmup property of the Auto Scaling group. The InstanceWarmup and DefaultInstanceWarmup properties work the same way. Only specify this property if you must override the DefaultInstanceWarmup property.

    If you do not specify this property, the instance warmup by default is the value of the DefaultInstanceWarmup property, if defined (which is recommended in all cases), or the HealthCheckGracePeriod property otherwise.

  • CheckpointPercentages (list) –

    (Optional) Threshold values for each checkpoint in ascending order. Each number must be unique. To replace all instances in the Auto Scaling group, the last number in the array must be 100.

    For usage examples, see Adding checkpoints to an instance refresh in the Amazon EC2 Auto Scaling User Guide.

    • (integer) –

  • CheckpointDelay (integer) –

    (Optional) The amount of time, in seconds, to wait after a checkpoint before continuing. This property is optional, but if you specify a value for it, you must also specify a value for CheckpointPercentages. If you specify a value for CheckpointPercentages and not for CheckpointDelay, the CheckpointDelay defaults to 3600 (1 hour).

  • SkipMatching (boolean) –

    (Optional) Indicates whether skip matching is enabled. If enabled ( true), then Amazon EC2 Auto Scaling skips replacing instances that match the desired configuration. If no desired configuration is specified, then it skips replacing instances that have the same launch template and instance types that the Auto Scaling group was using before the start of the instance refresh. The default is false.

    For more information, see Use an instance refresh with skip matching in the Amazon EC2 Auto Scaling User Guide.

  • AutoRollback (boolean) –

    (Optional) Indicates whether to roll back the Auto Scaling group to its previous configuration if the instance refresh fails or a CloudWatch alarm threshold is met. The default is false.

    A rollback is not supported in the following situations:

    • There is no desired configuration specified for the instance refresh.

    • The Auto Scaling group has a launch template that uses an Amazon Web Services Systems Manager parameter instead of an AMI ID for the ImageId property.

    • The Auto Scaling group uses the launch template’s $Latest or $Default version.

    For more information, see Undo changes with a rollback in the Amazon EC2 Auto Scaling User Guide.

  • ScaleInProtectedInstances (string) –

    Choose the behavior that you want Amazon EC2 Auto Scaling to use if instances protected from scale in are found.

    The following lists the valid values:

    Refresh

    Amazon EC2 Auto Scaling replaces instances that are protected from scale in.

    Ignore

    Amazon EC2 Auto Scaling ignores instances that are protected from scale in and continues to replace instances that are not protected.

    Wait (default)

    Amazon EC2 Auto Scaling waits one hour for you to remove scale-in protection. Otherwise, the instance refresh will fail.

  • StandbyInstances (string) –

    Choose the behavior that you want Amazon EC2 Auto Scaling to use if instances in Standby state are found.

    The following lists the valid values:

    Terminate

    Amazon EC2 Auto Scaling terminates instances that are in Standby.

    Ignore

    Amazon EC2 Auto Scaling ignores instances that are in Standby and continues to replace instances that are in the InService state.

    Wait (default)

    Amazon EC2 Auto Scaling waits one hour for you to return the instances to service. Otherwise, the instance refresh will fail.

  • AlarmSpecification (dict) –

    (Optional) The CloudWatch alarm specification. CloudWatch alarms can be used to identify any issues and fail the operation if an alarm threshold is met.

    • Alarms (list) –

      The names of one or more CloudWatch alarms to monitor for the instance refresh. You can specify up to 10 alarms.

      • (string) –

  • MaxHealthyPercentage (integer) –

    Specifies the maximum percentage of the group that can be in service and healthy, or pending, to support your workload when replacing instances. The value is expressed as a percentage of the desired capacity of the Auto Scaling group. Value range is 100 to 200.

    If you specify MaxHealthyPercentage, you must also specify MinHealthyPercentage, and the difference between them cannot be greater than 100. A larger range increases the number of instances that can be replaced at the same time.

    If you do not specify this property, the default is 100 percent, or the percentage set in the instance maintenance policy for the Auto Scaling group, if defined.

Return type:

dict

Returns:

Response Syntax

{
    'InstanceRefreshId': 'string'
}

Response Structure

• (dict) –

  • InstanceRefreshId (string) –

    A unique ID for tracking the progress of the instance refresh.

Exceptions

• AutoScaling.Client.exceptions.LimitExceededFault

• AutoScaling.Client.exceptions.ResourceContentionFault

• AutoScaling.Client.exceptions.InstanceRefreshInProgressFault

Examples

This example starts an instance refresh for the specified Auto Scaling group.

response = client.start_instance_refresh(
    AutoScalingGroupName='my-auto-scaling-group',
    DesiredConfiguration={
        'LaunchTemplate': {
            'LaunchTemplateName': 'my-template-for-auto-scaling',
            'Version': '$Latest',
        },
    },
    Preferences={
        'AlarmSpecification': {
            'Alarms': [
                'my-alarm',
            ],
        },
        'AutoRollback': True,
        'InstanceWarmup': 200,
        'MinHealthyPercentage': 90,
    },
)

print(response)

Expected Output:

{
    'InstanceRefreshId': '08b91cf7-8fa6-48af-b6a6-d227f40f1b9b',
    'ResponseMetadata': {
        '...': '...',
    },
}